Sub-assembly Parts

Sub-assembly parts represent the results of building your projects. Whenever you build a project, stock gets added to the corresponding sub-assembly part. The part can then be used in other projects, if needed.

This provides a way to build complex products that consist of a number of sub-assemblies and parts, each produced or sourced separately. As an example, let's say you build LED desk lamps, and your lamps are composed of:

• a control PCB
• a LED module PCB
• an enclosure

You would normally then have projects in PartsBox for "Control Module v1.1", another for "LED Module v1.3" and "Enclosure V1". Each one represents a fully assembled submodule of your final lamp.

After creating these projects, a single click in each enables the corresponding sub-assembly part. When you build, stock gets added to the sub-assembly part. You can also add stock manually (for items you already have).

Managing the build of the entire product is then easy: just create a project (let's call it "LAMP V1"), and add the sub-assembly parts:

• "Control Module v1.1"
• "LED Module v1.3"
• "Enclosure V1"

PartsBox will let you know (based on current stock levels) how many lamps you can build. When building, stock for sub-assemblies will be taken off.

What happens if you later start making "Control Module v1.2", and want newer lamps to accept either version 1.1 or 1.2 of the control module? No problem! Just define a meta-part containing both "Control Module v1.1" and "Control Module v1.2" and add that meta-part to your lamp project. The modules will then be treated interchangeably.

There is no limit to nesting depth, so if you have multi-level assemblies, PartsBox will take care of them.

Isn't it better to have a hierarchical BOM?

If all you do is work with a single BOM, maybe. But if you want to manage production of multiple projects, which might have common sub-components, any approach based on a hierarchical BOM will be limiting.

Sub-assembly parts in PartsBox behave just like normal parts. You can:

• attach documents/files to them
• add/remove stock
• see their entire stock history
• set low-stock alerts
• set attrition parameters
• include them in any other project/BOM

Thanks to sub-assembly parts, you can also reuse BOMs (use a sub-assembly in several larger projects), manage multiple versions of each module, and have BOMs which include any of the interchangeable versions. It is a significantly more flexible approach to managing production than a nested BOM.